Results 51 to 60 of about 1,834 (171)

Cepheid limb darkening, angular diameter corrections, and projection factor from static spherical model stellar atmospheres

, 2012
Context. One challenge for measuring the Hubble constant using Classical Cepheids is the calibration of the Leavitt Law or period-luminosity relationship.
Baade, Barmby, Barnes, Benedict, Bonanos, Burki, C.-C. Ngeow, Claret, Claret, Claret, Clement, Davis, Fouqué, Freedman, Getting, Gieren, Gieren, Gieren, Gray, Groenewegen, H. R. Neilson, Hindsley, J. Storm, Kanbur, Keller, Kervella, Kervella, Kovács, Kurucz, Leavitt, Lester, Marengo, Marengo, Marengo, Marengo, Mourard, Mérand, Mérand, Mérand, N. Nardetto, Nardetto, Nardetto, Nardetto, Nardetto, Neilson, Neilson, Neilson, Neilson, Neilson, Neilson, Ngeow, Ngeow, P. Fouqué, Parsons, Pietrzyński, Riess, Riess, Sabbey, Sasselov, Sasselov, Sasselov, Storm, Storm, Turner, van Leeuwen, Wesselink, Windmark   +66 more
core   +3 more sources

Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants [PDF]

, 2013
Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones.
Brown, Alexander, Drake, Stephen, Harper, Graham M., O'Gorman, Eamon, Richards, Anita M. S.   +4 more
core   +3 more sources

Stellar activity with LAMOST – II. Chromospheric activity in open clusters [PDF]

Monthly Notices of the Royal Astronomical Society, 2018
21 ...
Fang, Xiang-Song, Zhao, Gang, Zhao, Jing-Kun, Kumar, Yerra Bharat   +3 more
openaire   +2 more sources

Far-ultraviolet Emission Line Investigation of Flares on AU Mic

The Astrophysical Journal
The role of nonthermal proton energy transportation during solar and stellar flares is largely unknown; a better understanding of this physical process will allow us to rectify longstanding deficiencies in flare models.
Adalyn Gibson, Adam F. Kowalski, Adina D. Feinstein   +2 more
doaj   +1 more source

Solar Wind Heavy Ions and Alpha Particles Within Earth's Magnetosphere and Their Variability With Upstream Conditions

Journal of Geophysical Research: Space Physics, Volume 130, Issue 8, August 2025.
Abstract Working toward the goal of understanding solar wind (SW) entry to the Earth's magnetosphere, this study examines solar‐origin ion composition in the magnetotail. During its trajectory, Wind spent a significant amount of time in the Earth's magnetotail, where its SupraThermal Ion Composition Spectrometer (STICS) measured the mass and mass per ...
S. Colón‐Rodríguez, M. W. Liemohn, J. M. Raines, S. T. Lepri   +3 more
wiley   +1 more source

Measuring helium abundance difference in giants of NGC 2808 [PDF]

, 2011
Multiple populations have been detected in several globular clusters (GC) that do not display a spread in metallicity. Unusual features of their CMD can be interpreted in terms of differences in the Helium content of the stars belonging to the sub ...
Cacciari, C., Kaufl, H. U., Mauas, P., Pasquini, L.   +3 more
core   +2 more sources

Building Reliable Models of M Dwarf Chromospheres: The Spectral Diagnostics [PDF]

, 2000
As part of an ongoing project to study how reliable are the chromospheric models constructed semiempirically to fit the chromospheric spectrum of cold stars, in this paper we study how changes in the assumed chromospheric structure of dM and dMe stars ...
Mauas, Pablo Jacobo David
core   +1 more source

Slow Solar Wind: Origin in an Independent Small‐Scale Solar Dynamo

Geophysical Research Letters, Volume 52, Issue 13, 16 July 2025.
Abstract Separation of the solar wind (SW) into three flow types (coronal mass ejections (CMEs), high speed streams (HSSs), and slow solar wind (SSW)) reveals an inverse relationship between the percentage of time Earth spends in SSW during a year and its annually averaged magnetic field strength (B).
E. W. Cliver, I. G. Richardson, S. F. Martin   +2 more
wiley   +1 more source

Wavelet Analysis of Stellar Chromospheric Activity Variations

The Astrophysical Journal, 1997
Observations of chromospheric activity variations for some lower main-sequence stars from the Mount Wilson Observatory's HK project reveal a cyclic behavior comparable to the sunspot cycle. Even in the relatively short interval that they have been observed, those stars show stellar cycles and other features, like grand minima. The quasi-periodic nature
P. Frick, S. L. Baliunas, D. Galyagin, D. Sokoloff, W. Soon   +4 more
openaire   +1 more source

The Stagger Code for Accurate and Efficient, Radiation-coupled Magnetohydrodynamic Simulations

The Astrophysical Journal
We describe the Stagger code for simulations of magnetohydrodynamic (MHD) systems. This is a modular code with a variety of physics modules that will let the user run simulations of deep stellar atmospheres, sunspot formation, stellar chromospheres and ...
Robert F. Stein, Åke Nordlund, Remo Collet, Regner Trampedach   +3 more
doaj   +1 more source